Influence of disorders of visual perception in word-to-picture matching tasks in patients with Alzheimer's disease.

Patients affected by early Alzheimer's disease were given word-to-picture matching tasks in which the foils shared lexical-semantic, phonological, or visual-perceptual features with the target. The aim of the study was to evaluate the influence of the visual perceptual deficit in lexical comprehension tasks based on pictorial material. The results demonstrated that perceptual deficits are common in Alzheimer's disease. This finding is in agreement with the hypothesis that multiple modular deficits in Alzheimer's disease contribute to impaired comprehension.